the only mammals with powered flight, the evolutionary\xa0history of their wings has been poorly understood. However, research published Monday in Nature and PLoS Genetics has provided the first comprehensive look at the genetic origins of their incredible wings.But to appreciate the genetics of their wing development, it’s important to know how crazy a bat in flight truly\xa0looks.Try a little experiment: Stick your arms out to the side, palms facing forward, thumbs pointing up toward the ceiling. Now imagine that your fingers are\xa0long, arching down toward the floor like impossibly unkempt fingernails — but still made of bone, sturdy and spread apart. Picture the sides of your body connecting to your hands, a rubbery membrane attaching your leg and torso to those long fingers, binding you with strong, stretchy skin. Then, finally, imagine using your muscles to flap those enormous hands.Bats, man.As marvelous as bat flight is to behold, the genetic origins of their storied wings has remained murky. However, new findings from an international team of researchers led by Nadav Ahituv, PhD, of the University of California at San Francisco, Nicola Illing, PhD, of the University of Cape Town\xa0in\xa0South Africa\xa0and Katie Pollard, PhD of the UCSF-affiliated Gladstone Institutes has shed new light on how, 50 million years ago, bats took a tetrapod blueprint for arms and legs and went up into the sky.Using a sophisticated set of genetic tools, researchers approached the question of how bats evolved flight by looking not only at which genes were used in the embryonic development of wings, but at what point during development the genes were turned on and off, and — critically — what elements in the genome were regulating the expression of these genes. Genes do not just turn themselves on without input; genetic switches, called enhancers, act to regulate the timing and levels of gene expression in the body.',
"Since flight evolved millions of years ago in all of the groups that are capable of flight today, we can't observe the changes in behavior and much of the morphology that the evolution of flight involves. We do have the fossil record, though, and it is fairly good for the three main groups that evolved true flight. We'll spare you an in-depth description of how each group evolved flight for now; see the later exhibits for a description of each group and how they developed flight.",
"It's easy to forget that one in five species of mammal on this planet have wings capable of delivering spectacularly acrobatic flying abilities. Equally incredibly, two-thirds of these 1,200 species of flying mammal can fly in the dark, using exquisite echolocation to avoid obstacles and snatch airborne prey with stunning deftness. These amazing feats have helped make bats the focus not only of folkloric fascination, but also of biological enquiry and mimicry by human engineers from Leonardo da Vinci onwards. Recent research in PLOS journals continues to add surprising new findings to what we know about bats, and how they might inspire us to engineer manmade machines such as drones to emulate their skills. Bats, unlike most birds and flying insects, have relatively heavy wings – something that might appear disadvantageous. But a recent study in PLOS Biology by Kenny Breuer and colleagues shows that bats can exploit the inertia of the wings to make sharp turns that would be near-impossible using aerodynamic forces alone. The authors combined high-speed film of real bats landing upside-down on ceiling roosts with computational modelling to tease apart aerodynamic and inertial effects."],
["things, gold and silver, could buy a victory. And this Other Italian cities, inspired by Rome's example, overpowered occupying troops, shut their gates again and invited a second siege. Hannibal could not punish them without dividing his he had no competent leadership to do so, what with one member of",
'A group of Celts known as the Senone was led through Italy by their commander, Brennus. The Senone Gauls were threatening the nearby town of Clusium, when Roman Ambassadors from the Fabii family were sent to negotiate peace for Clusium. The Romans were notoriously aggressive, and so it is only a little surprising that when a scuffle broke out between the Gauls and Clusians, the Fabii joined in and actually killed a Senone chieftain. The Roman people voted to decide the fate of those who broke the sacred conduct of ambassadors, but the Fabii were so popular that they were instead voted to some of the highest positions in Rome. This absolutely infuriated Brennus and his people and they abandoned everything and headed straight for Rome. Rome was woefully unprepared for this sudden attack. The Gauls had marched with purpose, declaring to all the towns they passed that they would not harm them, they were heading straight for Rome.',
"Hannibal had no intention to sit and recieve the romans in spain.Hannibal clearly considered the nature of roman power-and came to the conclusion that Rome could only be defeated in Italy.The cornerstone of Rome's power was a strategic manpower base that in theory could produce 7,00,000 infantry and 70,000 cavalry.More than half of this manpower base (4,00,000) was provided by rome's Italian allies,who paid no taxes but had to render military service to rome's armies.Not all were content.Carthage on the other hand rarely used its own citizens for war,bulk of its army being mercenaries.In any case its manpower could never even come close to Rome,the fact that had aided roman victory in the 1st Punic war.Hannibal thus understood that Rome could afford to raise and send army after army to spain and take losses. Meanwhile any carthiginian losses in spain would encourage the recently conquered iberian tribes to defect. The only way to defeat Rome,was to fight in italy itself.By winning battle after battle on italian soil and demonstrating to the italian allies rome's inability to protect them and weakness,he could encourage them to break free of Rome eroding Rome's manpower to sizeable proportions. But there was one problem,his fleet was tiny and Rome ruled the seas.By land,the coastal route would be blocked by Roman forces and her ally-the great walled city of massalia.Hannibal thus resolved to think and do the impossible - move thousands of miles by land through the pyranees mountains,uncharted territory inhabited by the fierce gauls ,then through the Alps mountains and invade italy. Even before the siege of Saguntum had concluded,Hannibal had set things in motion.Having sent a number of embassies to the Gallic tribes in the Po valley with the mission of establishing a safe place for Hannibal to debouch from the Alps into the Po valley. He did not desire to cross this rugged mountain chain and to descend into the Po valley with exhausted troops only to have to fight a battle.Additionally the fierce gauls would provide a source of manpower for Hannibal's army.The romans had recently conquered much territory from the gauls in this area,brutally subjagating them ,seizing their land and redistributing it to roman colonists.Thus securing an alliance proved to be easy. After the sack of Saguntum he dismissed his troops to their own localities."]]